1. Field of the Invention
The present invention relates to solar cells. In particular, the invention relates to methods and apparatuses for solar cell concentrator arrays.
2. Description of the Related Art
Photovoltaic cells, commonly called solar cells, are well-known devices which convert solar energy into electrical energy. Solar cells have long been used to generate electrical power in both terrestrial and space applications. Solar cells offer several advantages over more conventional power sources. For example, solar cells offer a clean method for generating electricity. Furthermore, solar cells do not have to be replenished with fossil fuels. Instead, solar cells are powered by the virtually limitless energy of the sun.
In space applications, hundreds or thousands of the small solar cells are interconnected together to form large solar arrays. To increase the amount of power generated from these arrays, concentrators are often used. Concentrators increase the amount of light that falls on the array solar cells, which in turn generate increased electrical power.
Conventional concentrators often are implemented as reflectors. However, these conventional reflectors typically suffer from significant limitations. Conventional reflectors tend to be expensive, heavy, and hard to stow and deploy. Additionally, using one conventional technique, reflectors are positioned around the array, thereby causing reflected light to fall upon different cells with different intensities, causing solar cell hot spots. These hot spots may have to be cooled using complicated and heavy cooling mechanisms, such as heat pipes. Because of the great expense associated with lifting each pound of material into space, the real costs associated with these heavy systems are significant.
Using another conventional technique, rigid, thick reflectors, permanently extending two or more inches above the solar cells, may be placed at several locations on a solar cell array. This technique disadvantageously requires a great deal of stow room due to the height of the reflectors. Furthermore, the thick, heavy reflectors add significant weight to the array.
Still other conventional concentrator techniques use lenses positioned over the solar cells. These lenses may be relatively expensive and thick, and so disadvantageously add weight and height to the array panel. Lenses also require a relatively high degree of pointing accuracy to ensure that the solar cells receive the desired degree of focused light.